The Sigma DP3 Merrill packs a 46-megapixel Foveon image sensor and a fixed 75mm macro lens. It can capture amazing photos, but it's not a camera that will appeal to the masses.

By Jim FisherPerformance, Workflow, and ConclusionsThe DP3 is the slowest of the three DP Merrill cameras, because its lens has the furthest distance to travel in order to lock focus. It requires about 3.5 seconds to start up and shoot, records a 0.5-second shutter lag, and and can fire off a short burst of shots at about 3.8 frames per second. The Nikon Coolpix A starts faster at 1.5 seconds, but its shutter lag is a bit slower at 0.4-second.

The DP3 is capable of short bursts of 7 shots, but requires you wait quite a while for images to write to the memory card. This is the case even when you use a fast SanDisk 95MBps card like we do when testing camera speed. You'll have to wait about 34.9 seconds for a 7-shot JPG burst, and about 47 seconds for Raw or Raw+JPG to transfer from the internal buffer to the memory card. You can take another photo after the first has cleared, so you'll be locked out of shooting for about 5 seconds after a full JPG burst or 6.5 seconds for Raw+JPG.

In terms of focus speed, its 0.5-second shutter lag accounts for a focus confirmation and shot in good light. In dim light the focus speed dips to a lenghty 2.9 seconds. The DP2 Merrill is faster to focus; it locks on in about 0.3-second in good light and about 1.8 seconds in dim light.

I used Imatest to check the sharpness of the camera's JPG output at its base ISO setting of 100. Images were incredibly sharp, registering 2,404 lines per picture height at f/2.8; 1,800 lines is our cutoff for an acceptably sharp photo. Resolution peaks at f/4; the camera records 2,610 lines there. At f/5.6 it manages 2,521 lines, and going all the way down to f/8 will net you 2,502 lines. It's not the sharpest of the three Merrill cameras; that's the DP2, which peaks at 2,940 lines at f/5.6.

Imatest also measures noise, which robs detail and makes images look grainy when it crosses the 1.5 percent threshold. Despite sharing the same image sensor, the DP3 Merrill does a better job at handling image noise than its sibling the DP1 Merrill. It keeps noise below 1.5 percent through ISO 400, and images at ISO 800 clock in at a very respectable 1.6 percent. Detail is well preserved through ISO 800, although when you push the camera to ISO 1600 colors start to fade, and images at ISO 3200 and ISO 6400 are downright atrocious in terms of color fidelity and noise. You'll likely want to shoot Raw when you're working with this camera, however, as it will let you get the most out of the image sensor.

If you convert Raw images to TIFF using Sigma's Raw converter at default settings, noise is less of an issue. It's only 1 percent at ISO 800, and you can control it a bit more by applying some software noise reduction. The DP1 Merrill's JPG engine isn't as refined; it can only control noise at ISO 100, but processing images in Raw yield very similar results to the DP3. That makes a lot of sense, when you consider that the two cameras use the same image sensor.

When you shoot JPG, you're throwing away a lot of the information that's captured by the Foveon sensor. To get the most out of this camera, you'll really want to shoot in Raw. Normally this wouldn't be a major black mark, but because the Foveon sensor design is unique to Sigma cameras, only the Sigma Photo Pro application supports the format—and that software leaves a lot to be desired in terms of editing. The Sigma software isn't the most intuitive, is rather slow, and lacks a lot of the finer editing features—including degree-by-degree rotation, spot correction, and graduated filters—that are available in Lightroom. You'll need to devote quite a bit of storage space using this method—each Raw file is around 50 megabytes and a 16-bit TIFF is closer to 90MB in size—that's 140MB per shot.

When properly processed, you can pull an incredible amount of detail out of the Raw files—see the slideshow for an image and a 100 percent crop that demonstrate what the DP3 Merrill is capable of. If you capture a high volume of images and rely on batch Raw processing tools—or JPG shooting—to speed your workflow, the DP3 will likely frustrate you. But if you tend to spend a good amount of time perfecting each photo, the camera will better suit your style.

You'll have to learn the how to best process your files to appreciate them, and you'll still deal with a few quirks of the Foveon design. The red channel is especially prone to clipping, but you can dial down contrast just a little bit in Sigma's software in order to prevent this from happening. In order to get the best results from the DP2, Sigma's engineers recommend that you set Sharpening to -1 or -1.5 in Sigma Photo Pro, and later apply sharpening in Lightroom. They also recommend dropping color saturation down one or two notches, and to set noise reduction at its lowest for photos shot at ISO 100 or 200, but to leave it in its default setting when shooting at higher ISOs. This methodology was followed for the sample images in the slideshow.

The DP3 Merrill can record video, but it's not where this camera excels. Resolution is limited to 480p30 in AVI format, and the internal microphone is pretty quiet compared with others. The footage lacks any pop in terms of color, and it shows some evidence of the rubber pencil effect, likely a result of the rolling shutter effect, during pans—the top of the frame will pan ahead of the bottom.

The only data connection on the camera is a proprietary interface that carries USB and video output using included cables. Standard SD, SDHC, and SDXC memory cards are supported.

Of the three Sigma Merrill cameras the DP3 appeals to the smallest niche. The DP1's 28mm-equivalent lens is a classic field of view that appeals to wide-angle photographers, and the DP2's 45mm-equivalent lens is pretty close to the 50mm prime that was the standard kit lens for many a manual focus 35mm SLR. That said, it's the only big-sensor compact on the market with a short telephoto prime lens, and the macro shooting capability is a nice bonus. If the idea of a 75mm fixed lens appeals to you, and if you're willing to work at low to mid ISO settings, and if you're willing to deal with the Sigma Photo Pro software, the DP3 will deliver stunning images. Those are a lot of ifs, but not every camera needs to be a crowd pleaser. If you're trying to find the perfect prime-lens compact for you and the DP3 doesn't sound like the right one, consider our Editors' Choice Ricoh GR, which sells for about $100 less; it has a fixed 28mm lens and a traditional Bayer image sensor. Shooters wa love for the 35mm field of view may want to go with the Sony Cyber-shot DSC-RX1; just be prepared to save your pennies or reach deep into your pockets, that full-frame compact sells for $2,800.

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